Characterization and modeling of the static and dynamic friction in a damper (original) (raw)
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Experimental Evaluation of New Friction Damper Device
A new friction damper device was designed to dissipate and absorb input energy in order to increase building safety. It can be used in retrofitting or in designing of new buildings. The friction damper was tested intensively in order to verify its characteristics and performance. This device consists of several steel plates that rotate against each other in opposite directions, producing friction between its parts. Utilization of this type of geometric deformation of the damper parts of frame displaced laterally, is a way to permit substantial controlled energy dissipation. The interfaces between the inner pieces of the device were faced by use of different materials such as brass or friction pad material. This device is characterized, especially when the friction pad material is used, by a very stable hysteric non-degrading behaviour over many cycles. It is also linearly dependent on displacement amplitude and normal load. Some velocity dependency was observed during tests, due to change of friction coefficient of sliding phase. The damper was implemented in a single story steel frame model. This frame is a 1/3-scale model of typical frame. It is connected to the frame by use of chevron-bracing system and prestressed bars were used instead of structural steel bracing sections. Harmonic loading was used to excite the frame. The response was studied for different values of parameters such as forcing frequencies, displacement amplitude, bolt-clamping force and prestressing bar force. In conclusion, using of supplemental damping provided by this friction damper, dissipate a big amount of kinetic energy in a structure, and thereby eliminate the utilization of structural ductility while the structure remain elastic without damage.
Experimental response of friction dampers under different loading rates
International Journal of Impact Engineering, 2019
This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain. Highlights Experimental campaign of friction dampers under quasi-static and impact loads. Variation of the geometry and coating materials of the tested specimens; Under impact loading, the friction damper showed more brittle behaviour;
Parameters influencing the behavior of a new friction damper device
Smart Structures and Materials 2000: Smart Systems for Bridges, Structures, and Highways, 2000
This work presents a study on the parameters that govern the performance of a new Friction Damper Device (FDD). The device was designed to dissipate seismic input energy and protect buildings from structural and nonstructural damage during moderate and severe earthquakes. The device consists of 3 steel plates that rotate against each other in different directions, and in between these plates, friction pad material discs are inserted. The damper is attached to structures by using inverted Chevron bracing system and in this work pre-stress bars were used as bracing members. The clamping force in the pretensioned bolt controls the frictional moment at the onset of sliding.
Experimental analysis on friction materials for supplemental damping devices
Construction and Building Materials, 2014
In this paper, the friction coefficient and the cyclic response of different interfaces for friction devices are investigated by means of experimental tests under displacement control. In particular, six interfaces have been tested: steel-steel, brass-steel, sprayed aluminum-steel and three different rubber based friction materials adopted, respectively, in automotive applications, electrical machines and applications requiring low wearing. Static and kinetic friction coefficients have been evaluated and the influence of the interface pressure has been analyzed. The variation of the sliding force during the cyclic loading history has been investigated by comparing also the response coming from the use of different washers: circular flat washers and cone shaped annular disc springs. The work is aimed at the investigation of friction materials to be applied within the connecting elements of beam-to-column joints according to the double split tee configuration with friction pads.
Analysis and optimization of the effects of frictional and viscous dampers on dynamical systems
Journal of Low Frequency Noise, Vibration and Active Control, 2019
Over the last several years, the complexity of products has been increasing in parallel to the product cost thus becoming one of main focal points for development. On the other hand, although several applications struggle to fix vibration problems, highlighting the importance of damper design, literature that compares the benefits and disadvantages between of dry-frictional, viscous, and Coulomb–viscous dampers is still rare. Owing to this, the main goal of this work is to present a study that compares the dynamical response of mechanical systems against several damper types. For this research, we analyzed the effects of three types of damper (viscous, Coulomb–viscous, and dry-frictional dampers) on two mechanical systems. The first system consists of a mass-spring-damper with one degree of freedom, while the second system is a rotational machine with three degrees of freedom. The sensibility analyses of each damper were also studied, where the viscosity, Coulomb force, static frict...
A friction damping system for reduction of the response of dynamic loaded structures is studied, the key parameters are identified and the design is discussed.
2008
A friction damper is regarded as one of the most effective structural control devices in view of regulating the inertia force induced from the upper structures and effective energy dissipation. Despite a large number of friction dampers or bearings have been used for civil and architectural structures, those devices generally require large deformation and stable vertical load induced on the device in order to attain a desirable control performance. In order to overcome such difficulties, a new friction-based damper was developed. The new damper has several steel arms that are linked each other by a bolt in order for them to rotate freely, and carefully manufactured disk friction materials are embedded in that link. By connecting these arms to the upper and lower structures, horizontal deformation of the structure is converted into the rotational motion of the link and disk. The damper requires significantly less space for installation compared to the traditional friction dampers in ...
Experimental assessment of friction dampers under impact loading
ce/papers, 2017
In order to enhance the knowledge of the behaviour of steel joints under accidental loading conditions, within the European research project FREEDAM, the behaviour of an innovative beam-to-column connection, in particular the dissipative component (friction damper) of the joint under tension, has been studied under impact and quasi-static conditions. This experimental campaign comprises a total of 6 quasi-static tests and 35 impact tests on friction pads, that includes three different friction materials, two different plate thicknesses (10mm and 30mm) and two different bolt classes (class 8.8SB or 10.9HR). The impact tests were performed using an experimental layout capable of apply high loading rates by a pneumatic actuator, totally developed and tailored at the University of Coimbra. The results of impact tests compared with the quasi-static tests show: i) an increase in the component resistance when subjected to impact loads, ii) a reduction in the ductility of the component.